Pavement marker and system for freeway advance accident merge signal

ABSTRACT

A pavement marker includes a support structure adapted to be mounted on a highway pavement intermediate first and second highway lanes in a position visible to oncoming traffic. One or more red and yellow lights are directed toward the oncoming traffic. A sensor on it senses nearby traffic. A receiver on it receives an incoming signal from a first companion pavement marker that is mounted on the highway pavement more distant from the oncoming traffic. A transmitter on it transmits an outgoing signal to a second companion pavement marker that is mounted on the highway pavement less distant from the oncoming traffic. A solar-charged, battery-powered circuit controls operation according to information from the sensor and the receiver in order to relay advance warning of slowed, stopped, and all-clear traffic conditions to the oncoming traffic via multiple spaced-apart pavement markers.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to highway design and construction, and more particularly to a pavement marker and system for automatically providing a multi-lane highway merge signal to drivers.

2. Description of Related Art

A driver on a multi-lane highway must often merge left or right into an adjacent lane when approaching the scene of an automobile accident, debris on the pavement, or other obstacle that causes traffic to slow down. Doing so can be extremely dangerous, especially during rush hour and at highway speeds. In order to alleviate this concern, portable and fixed programmable signs are sometimes used along the freeway to forewarn drivers of an obstacle ahead.

However, the portable and fixed programmable sign approach has certain drawbacks. Although, a portable sign can sometimes be quickly dispatched to an accident scene, doing so nevertheless takes a significant amount of time. Fixed signs, on the other hand, are useable only in the location where they are erected. In addition, both portable and fixed signs must be programmed at the time needed with the message they are to display.

There are numerous existing methods and warning devices of road hazard warning systems. For example, there are lighted test signs that indicate the location of highway problems, merge signs on stationary or moving vehicles, traffic stations on the radio, and periodic traffic updates on various radio stations. But, there is no instant warning system for the incoming driver as an accident happens. Thus, a need exists for a better way to provide an advance warning in the form of an automatic merge signal to freeway drivers.

SUMMARY OF THE INVENTION

This invention addresses the concerns outlined above by providing a pavement marker that combines with similar companion pavement markers to provide the desired merge signal. The pavement markers are disposed at space-apart locations along lane-dividing lines on the highway. Each pavement marker is a solar-charged, battery-powered device outfitted with a traffic sensor, red and yellow lights, transmitter and receiver modules, and control circuitry. Each pavement marker communicates with adjacent pavement markers to relay a traffic warning about slowed or stopped vehicle, illuminating the red and yellow lights appropriately to provide a freeway advance accident merge signal (FAAMS) to drivers.

To paraphrase some of the more precise language appearing in the claims and further introduce the nomenclature used, a pavement marker constructed according to the invention includes a support structure adapted to be mounted on a highway pavement intermediate first and second highway lanes in a position visible to oncoming traffic. A light-emitting circuit is provided on the support structure for producing a light directed toward the oncoming traffic, together with a sensor for sensing nearby traffic in order to provide information related to nearby vehicle speed, a receiver for receiving an incoming signal from a first companion pavement marker that is mounted on the highway pavement more distant from the oncoming traffic in order to receive information related to traffic conditions more distant from the oncoming traffic than the support structure. A transmitter is provided in addition for transmitting an outgoing signal to a second companion pavement marker that is mounted on the highway pavement less distant from the oncoming traffic in order to transmit outgoing information related to traffic conditions. A battery-powered, solar-charged circuit on the support structure controls operation of the light-emitting circuit and the transmitter according to information obtained from the sensor and the receiver in order to provide advance warning of traffic conditions to the oncoming traffic via multiple pavement markers.

Preferably, the electronic circuit is adapted to control operation under program control and the light-emitting circuit includes at least one red light-emitting component and at least one yellow light-emitting component. In one embodiment, the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for more than a first predetermined period of time (e.g., 30 seconds) by activating the light-emitting circuit and transmitting an INITIAL OUTGOING SLOWED-VEHICLE signal to the second companion pavement marker.

In addition, the electronic circuit is preferably adapted to respond to the receiver receiving an INCOMING SLOWED-VEHICLE signal from the first companion pavement marker by activating the light-emitting circuit, disregarding the sensor, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of the new counter valve to the second companion pavement marker. The electronic circuit is adapted to not transmit the RELAYED OUTGOING SLOWED-VEHICLE signal if the counter valve reaches a predetermined maximum valve (e.g., 200) so that the slowed traffic information is only relayed toward the oncoming traffic by that number of pavement markers.

Preferably, the electronic circuit is also adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for less than the first predetermined period of time after transmitting the INITIAL OUTGOING SLOWED-VEHICLE signal by deactivating the light-emitting circuit and transmitting an ALL-CLEAR signal to the second companion pavement marker. Operation is preferably similar in the case of a stopped vehicle. The electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for more than a second predetermined period of time (e.g., 90 seconds) by activating the light-emitting circuit and transmitting an INITIAL OUTGOING STOPPED-VEHICLE signal to the second companion pavement marker.

Thus, the invention provides a pavement marker that combines with similar companion pavement markers to provide the desired merge signal. Each pavement marker communicates with adjacent pavement markers to relay a traffic warning about slowed or stopped vehicle, illuminating the red and yellow lights appropriately to provide a freeway advance accident merge signal (FAAMS) to drivers.

The invention provides immediate warning, miles ahead, to incoming traffic that there is a hazard on the road or a blocked lane ahead. It keeps the traffic flowing more smoothly by indicating to the incoming traffic which lane is blocked due to a stalled vehicle, accident, or other problem affecting the flow of traffic in a particular lane. Incoming traffic is able to smoothly and gradually merge toward the open lanes because the system of this invention specifically indicates which lane is blocked so that drivers will be able to avoid that lane. Motorists will be less likely to miss the warning indicators because they are always in front of them. For tunnels, curved roads, or unlit roads, the system gives warning prior to entering the blind areas. The following illustrative drawings and detailed description make the foregoing and other objects, features, and advantages of the invention more apparent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 of the drawings is an isometric view of a pavement marker constructed according to the invention;

FIG. 2 is a blown apart view of the pavement marker;

FIG. 3 is a block diagram of the pavement marker;

FIG. 4 is a circuit diagram that illustrates suitable circuitry;

FIGS. 5 a, 5 b, 5 c, and 5 d combine at points labeled A, B, C, and D to form a flow chart that is descriptive of software in the program memory in the microcontroller portion of the control circuitry;

FIG. 6 is a diagrammatic representation of a four-lane highway having two left bound lanes and two right bound lanes separated by lane dividers, with pavement markers disposed at intervals along the lane dividers;

FIG. 7 is a diagrammatic representation similar to FIG. 6, but with the traffic in the innermost left bound lane (i.e., the first left bound lane) slowed; and

FIG. 8 is a diagrammatic representation similar to FIG. 6, but with the traffic in the first left bound lane stopped.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-7 of the drawings show various aspects of a pavement marker 10 constructed according to the invention.

Generally, the pavement marker 10 includes a support structure in the form of a housing 11 (e.g., metal) and a circuit module 12 on the housing 11 (FIGS. 1 and 2). Those components may be similar in some general respects to existing pavement markers, including the pavement marker described in U.S. Pat. No. 6,602,021.

The housing 11 is adapted to be mounted on a highway pavement intermediate first and second highway lanes in a position visible to oncoming traffic. It is so adapted in the sense that it is sufficiently rigid, durable, and small to present a low profile and withstand vehicles driving over it (inadvertently or when changing lanes). It may be similar structurally to existing pavement markers in that respect.

The circuit module 12 within the housing 11 includes a battery-powered, solar-charged circuit that is described later on with reference to FIGS. 3, 4, and 5 a-5 d. The circuit module 12 fits into a main section 13 of the housing 11 with a solar panel 14 portion of the circuit (also described later on) facing upwardly. A bottom cover 15 is mounted on the main section 13 of the housing 11 to retain the circuit module 12 in place.

A lens 16 is mounted on a first side 17 of the main section 13 over a first light-emitting circuit 18 (e.g., multiple red LEDs) and a second light-emitting circuit 19 (e.g., multiple yellow LEDs) on the circuit module 12 to face oncoming traffic. An RF-transparent plate 20 is mounted on an opposite second side 21 where it admits an incoming RF signal to the circuit module 12 as described later on. An opening 22 is provided in the main section 12 through which a sensor 23 on the circuit module 14 operates in sensing the presence of nearby vehicles.

As an idea of size, the illustrated housing 11 measures about five to six inches on each side and about one inch in height. Of course, those dimensions may vary without departing from the invention. Based upon the foregoing and subsequent descriptions, one of ordinary skill in the art can readily implement the housing aspects (i.e., the support structure aspects) of the invention.

Turning now to the block diagram in FIG. 3, it shows further details of battery-powered, solar charged circuitry on the circuit module 12. The solar panel 14 charges a battery 25 that powers a control circuit 26. The control circuit 26 receives a sensor signal from the sensor 23 and a receiver signal from a receiver 27 located toward the RF transparent plate 20 shown in FIGS. 2 and 3. The control circuit 26 responds to the sensor signal and the receiver signal (received from a companion pavement marker located more distant from oncoming traffic than the pavement marker 10) by turning on and off the first or red light-emitting circuit 18 and the second or yellow light-emitting circuit 19 according to traffic conditions. It also causes a transmitter 28 (located toward the lens 16) to transmit a related transmitter signal to a companion pavement marker less distant from oncoming traffic.

FIG. 4 is a schematic circuit diagram of a breadboard model 30 of the control circuitry shown in FIG. 3 that illustrates a suitable circuit arrangement. It uses known components and design techniques to achieve the functions desired. A commercially available programmable microcontroller 31 is used to simulate the primary part of the control circuit 26. The microcontroller 31 is powered by a 6-volt battery pack 32 (representing the battery 25 in FIG. 3), and the battery pack 32 is, in turn, charged by a solar panel 33 (e.g., 5 volts at 180 milliampere). An on/off switch 34 is provided for convenience.

The microcontroller 31 controls (under program control) a commercially available 12-bit encoder 35 and a commercially available 12-bit decoder 36. The encoder 35 encodes information that is coupled to a commercially available transmitter module 37 (e.g., a 300 MHz AM transmitter) for encoding on a transmitter signal transmitted by the transmitter module 37. The decoder 36 decodes information encoded on a receiver signal that the decoder 36 receives from a commercially available receiver module 38 (e.g., a 300 MHz AM receiver).

A commercially available sensor 39 supplies a sensor signal to the microcontroller 31 that is indicative of the speed of a nearby vehicle. The microcontroller 31 uses information derived from the sensor signal and the receiver signal to turn on and off a first light-emitting circuit (e.g., a plurality of commercially available ultra-bright red light-emitting LEDs 40) and a similar second light-emitting circuit (e.g., a plurality of ultra-bright yellow light-emitting LEDs 41), in addition to causing the transmitter module 37 to transmitter a transmitter signal. Based upon the foregoing and subsequent descriptions, one of ordinary skill in the art can readily implement suitable circuitry for the pavement marker 10.

The microcontroller 31 is programmed according to know programming techniques to perform the functions desired. FIGS. 5 a, 5 b, 5 c, and 5 d combine at points labeled A, B, C, and D to form a high level flow chart that is descriptive of software in the program memory in the microcontroller 31. The program start (block 41 in FIG. 5 a) is the section of the software in the program memory that lists the specific microcontroller type that is used along with the name of the INCLUDE file. One of ordinary skill in the art will recognize that these configurations are necessary when the software is transferred from a personal computer used for programming purposes to the microcontroller 31. The program start (block 41) also states the variable assignments. The variable assignments give the variable letter designation of all the variables used in the program along with their location in the program memory.

The mainline program (block 42) starts the primary subroutine of the program and denotes the beginning of that particular section of the program. The setting initial values (block 43) sets initial valves for each of the variables assigned in block 41.

These variables and their initial values are used to perform a variety of tasks throughout the execution of the program. The port initialization (block 44) is performed for each port used by the program on the microcontroller. Port initialization configures the pins of the microcontroller 31 so that they are capable of performing the particular tasks needed by the software in the program memory of the microcontroller 31.

The main LOOP (block 45) is a subroutine that is part of the mainline program in 42. The main LOOP repeats its execution until an interrupt request is received by the microcontroller 31 via the receiver module 38 from an up-line unit (i.e., a first companion pavement marker that is more distant from oncoming traffic). Once the interrupt is complete the program continues to execute the main LOOP. The specific code that is executed as parts of the main LOOP is explained for the read sensor (block 46 in FIG. 5 a) and for the blocks in FIGS. 5 c and 5 d. The proximity sensor value (the voltage of the sensor signal from the sensor 39) is read by the microcontroller 31 approximately three times per second (block 46). The proximity sensor sends the sensor valve as an analog voltage value to one of the pins of the microcontroller 31. The microcontroller 31 reads that value and compares it to a fixed value to determine if an object is within predetermined range specifications.

The interrupt routine (block 47 in FIG. 5 b) is the section of the software in the program memory of the microcontroller 31 that handles communications sent from the up-line unit. The up-line unit transmits the value of a traffic-delay-indicating variable D to the pavement marker 10 which is down-line from it (i.e., closer to oncoming traffic). The microcontroller 31 then interrupts its execution of the main LOOP at block 45 to read the value of D into the microcontroller. The interrupt routine only returns to the main LOOP at block 45 when a zero value for variable D is read by the unit that receives the interrupt request. A value of zero for variable D then turns OFF the red or yellow LEDs. When an interrupt request is received by the microcontroller 31 via the receiver module 38 and the decoder 36, the value is read and transferred into the register of variable D. The value of variable D is then compared to fixed values pre-programmed into the software in the program memory of the microcontroller 31.

The value of variable D received during the interrupt request is compared. If the value of variable D is greater than 5, then the Yellow LEDs are turned ON (block 49), and the value of variable D greater than 5 is sent to the output pins of the microcontroller 31. The encoder 35 that is connected to the output pins of the microcontroller 31 sends the value of variable D to the wireless transmitter module 37 for transmission to command the down-line unit (the second companion pavement marker that is less distant from oncoming traffic) to turn ON its yellow LEDs (block 49A). Following the transmission of the value of variable D to the down-line unit, the software in the program memory of the microcontroller 31 waits for another interrupt request from the adjacent up line unit (block 50). The interrupt request received from the up-line unit will either tell the unit to turn ON the red LEDs or turn OFF the red or yellow LEDs and return to the main LOOP subroutine.

If the value of variable D that is read during the interrupt request is between 1 and 5, then the red LEDs are turned ON (block 51). The value of variable D between 1 and 5 is sent to the output pins of the microcontroller 31 that is connected to the encoder 35. The encoder 35 then sends the value of variable D to the wireless transmitter module 37 for transmission to command the down-line unit to turn ON the red LEDs (block 51A). Following the transmission of the value of variable D to the adjacent down line unit the software in the program memory of the microcontroller 31 waits for another interrupt request from the up-line unit (block 52). The interrupt request received from the up-line unit will command the unit to turn OFF the red LEDs.

If the value of D that is read during the interrupt request is is zero, then the red or yellow LEDs are turned OFF depending on which one was turned ON prior to being turned OFF (block 52). The value of variable D that is equal to zero is sent to the output pins of the microcontroller 31 that are connected to the encoder 35. The encoder 35 then sends the value of variable D to the wireless transmitter module 37 (block 53A) for transmission to the down-line unit to command the down-line unit to turn OFF the red or yellow LEDs, depending on which one is turned ON prior to being turned OFF. The CALL command for the main LOOP (block 54) moves the program counter to the beginning of the LOOP subroutine to repeat the execution of the subroutine. The subroutine LOOP is repeated continuously until an interrupt request is received from the up-line unit via the receiver module 38 that commands the unit to turn ON the red or yellow LEDs, or turn them OFF.

The analog voltage value read by the microcontroller 31 is compared (block 55 in FIG. 5 c) to fixed values pre-programmed into the software in the program memory of the microcontroller 31. The sensor voltage values compared are those less than 0.6 volts (a predetermined minimum value) and greater than 2.5 volts (a predetermined maximum value). Depending on the sensor's voltage level read by the microcontroller 31, the red LEDs or yellow LEDs are turned OFF (block 56). If the voltage level of the sensor is read to be less than 0.6 volts or greater than 2.5 volts during a sample taken three times per second, then the red or yellow LEDs are turned OFF if they were already turned ON. When a change in the state to turn OFF the red or yellow LEDs is detected, a value of zero is transferred to the register of variable D. That value of variable D is then transmitted (block 57) to command the down-line unit to turn OFF the red or yellow LEDs. The value of variable D is transmitted through the output pins of the microcontroller 31 connected to the encoder 35. The encoder 35 is connected to the wireless transmitter module 37 that transmits the value of variable D to the down-line unit. When a wireless transmission to the down-line unit is complete, the program repeats the main LOOP subroutine from the beginning (block 58). It goes to block 45 in FIG. 5 a and repeats the code execution.

At block 59 FIG. 5 d, the sensor's analog voltage value read by the microcontroller 31 and compared to the fixed values pre-programmed in the software of the microcontroller 31. If the voltage level of the sensor is between 0.6 volts and 2.5 volts, then an object (e.g., a vehicle) is within a pre-specified range. If the voltage read by the microcontroller 31 is between 0.6 volts and 2.5 volts then the value of a timing variable X is incremented by one.

At block 60, the value of variable X is compared to a predetermined variable value of T representing a predetermined minimum period of time (e.g., 30 seconds). If the value of variable X is less than the value of variable T then a CALL command is executed for the subroutine LOOP to repeat the LOOP subroutine again to read another sample voltage level from the sensor. At block 61, the value of variable X is compared to a predetermined variable value Y representing a predetermined maximum period of time (e.g., 90 seconds). If the value of variable X is greater than the value of variable Y, then the red LEDs are turned ON. The value of variable D is then set to two. The value placed in the register of variable D is then transmitted to the down-line unit (block 62) to command the units to turn ON their red LEDs. The value of D is sent via the output pins of the microcontroller 31 connected to the encoder 35. The encoder 35 is connected to the wireless transmitter module 37 that transmits the value of variable D to the down-line unit. The CALL command for the main LOOP (block 63) moves the program counter to the beginning of the LOOP subroutine to repeat the execution of the subroutine. The subroutine LOOP is repeated continuously until an interrupt request is received from an adjacent up line unit that commands the unit to turn ON the red or yellow LEDs, or to turn them OFF.

At block 64, the value of variable X is compared to fixed variable values T and Y. If the value of variable X is greater than variable T and less than variable Y, the yellow LEDs are turned ON and the value of variable D is set to 6. The value placed in the register of variable D is then transmitted to the down-line unit (block 65) to command the down-line unit to turn ON the yellow LEDs. The value of variable D is sent through the pins of the microcontroller 31 connected to the encoder 35. The encoder 35 is connected to the wireless transmitter module 37 that transmits the value of variable D to the down-line unit. The CALL command for the main LOOP (block 66) moves the program counter to the beginning of the LOOP subroutine to repeat the execution of the subroutine. The subroutine LOOP is repeated continuously until an interrupt request is received from an adjacent up-line unit that commands the unit to turn ON the red or yellow LEDs, or to turn them OFF. Based upon the foregoing, one of ordinary skill in the art can readily program the microcontroller 31 to function as desired.

Operation is illustrated pictorially in FIGS. 6, 7, and 8 for traffic on a typical highway having two lanes in a first direction (that is left bound from the viewpoint of a reader) and two lanes in a second direction that is right bound from the viewpoint of the reader. First consider FIG. 6. It shows the highway having a central highway divider 70 (e.g., a median strip) between left bound and right bound traffic. A first left bound lane 71 on a first side of the highway divider 70 is bounded on the left side of traffic by a first left bound lane divider line 72. A second left bound lane 73 is bounded on the left side of traffic by a second left bound lane divider line 74 on the left side of traffic in the second left bound lane 73. First and second right bound lanes 75 and 76 on an opposite side of the highway divider 70 are arranged in a similar manner.

Pavement markers 73A through 73F are mounted on the highway pavement at uniformly spaced-apart intervals on the first lane divider line 72. Pavement markers 74A through 74F are mounted on the highway pavement at uniformly spaced-apart intervals on the second lane divider line 74. The resulting lines of spaced-apart pavement markers continues in both directions with additional pavement markers (not shown).

Vehicles 81 and 82 (and vehicles following after them) are oncoming traffic relative to the pavement markers 73A, 73B, and 73C. Similarly, vehicles 83 and 84 (and vehicles following after them) are oncoming traffic relative to pavement markers 74A, 74B, and 74C. Focusing on the pavement marker 73C as representing the pavement marker 10 described above, the pavement marker 73B represents the first companion pavement marker mentioned previously that is located more distant from the oncoming traffic. Similarly, the pavement marker 73D represents the second companion pavement marker mentioned previously that is located less distant from the oncoming traffic.

In operation, the pavement marker 73C senses the presence of a nearby vehicle 83 as that vehicle passes by the pavement marker 73B. If the vehicle 83 is sensed for less than 30 seconds, red and yellow lights remain off. If the vehicle 83 is sensed between 30 seconds and 90 seconds, however, the yellow light is turned on and an INITIAL OUTGOING SLOWED-VEHICLE signal is transmitted to the second companion pavement marker 73D for relay to pavement markers 73E and 73F, and onward down-line toward oncoming traffic between a predetermined number (e.g., 200) of companion pavement markers. The pavement marker 73D receives that signal as an INCOMING SLOWED-VEHICLE signal and it responds by disregarding the sensor signal from its own sensor, activating its yellow light, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of the new counter valve to the next down-line companion pavement marker 73E. The pavement marker 73F receives the RELAYED OUTGOING SLOWED-VEHICLE signal as an INCOMING SLOWED-VEHICLE signal and responds in much the same way. The yellow-light-on state is depicted in FIG. 7 by cross hatching on the pavement markers 73C, 73D, 73E, and 73F.

If the vehicle 83 is sensed for more than 90 seconds, the yellow light is turned off, the red light is turned on and an INITIAL OUTGOING STOPPED-VEHICLE signal is transmitted to the second companion pavement marker 73D for relay to pavement markers 73E and 73F, and onward down-line toward oncoming traffic between the predetermined number of companion pavement markers in a manner similar to that described above for slowed traffic. The pavement marker 73D receives that signal as an INCOMING STOPPED-VEHICLE signal and it responds by disregarding the sensor signal from its own sensor, activating its red light, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING STOPPED-VEHICLE signal indicative of the new counter valve to the next down-line companion pavement marker 73E. The pavement marker 73F receives the RELAYED OUTGOING STOPPED-VEHICLE signal as an INCOMING STOPPED-VEHICLE signal and responds in much the same way. The red-light-on state is depicted in FIG. 8 by a black fill for the pavement markers 73C, 73D, 73E, and 73F.

Eventually, traffic begins to move again after a slowed or stopped state. When that happens, the pavement marker 73C responds to its sensor detecting an occurrence of the presence of a nearby vehicle for less than the 30 seconds by deactivating its light-emitting circuit (i.e., its red or yellow light) and transmitting an ALL-CLEAR signal to the second companion pavement marker for relay toward the oncoming traffic so that the other pavement markers also deactivate their light-emitting circuits.

Thus, the invention provides a pavement marker that combines with similar companion pavement markers to provide the desired merge signal. Each pavement marker communicates with adjacent pavement markers to relay a traffic warning about slowed or stopped vehicle, illuminating red and yellow lights appropriately to provide a freeway advance accident merge signal (FAAMS) to drivers.

Although an exemplary embodiment has been shown and described, one of ordinary skill in the art may make many changes, modifications, and substitutions without necessarily departing from the spirit and scope of the invention. Communication between modules using infrared signals may be use instead of RF signals, for example, thereby eliminating the use of address settings for each unit. In addition, various sophisticated refinements in program logic may be included, these things being within the capability of one of ordinary skill in the art. 

1. A pavement marker, comprising: a support structure adapted to be mounted on a highway pavement intermediate first and second highway lanes in a position visible to oncoming traffic; means on the support structure for producing a light directed toward the oncoming traffic, including at least one light-emitting circuit; means on the support structure for sensing nearby traffic in order to provide information related to nearby vehicle speed, including a sensor; means on the support structure for receiving an incoming signal from a first companion pavement marker that is mounted on the highway pavement more distant from the oncoming traffic, including a receiver; means on the support structure for transmitting an outgoing signal to a second companion pavement marker that is mounted on the highway pavement less distant from the oncoming traffic, including a transmitter; and means on the support structure for controlling operation of the light-emitting circuit and the transmitter according to information obtained from the sensor and the receiver in order to provide advance warning of traffic conditions to the oncoming traffic, including an electronic circuit with a circuit-powering battery and a battery-charging solar cell assembly; wherein the electronic circuit is adapted to control operation under program control in order to relay the information related to nearby vehicle speed from the first companion marker to the second companion marker and thereby relay the information toward oncoming traffic as an advance warning of traffic conditions ahead of the oncoming traffic.
 2. (canceled)
 3. A pavement marker as recited in claim 1, wherein the light-emitting circuit includes at least one red light-emitting component and at least one yellow light-emitting component.
 4. A pavement marker as recited in claim 1, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for more than a first predetermined period of time by activating the light-emitting circuit and transmitting an INITIAL OUTGOING SLOWED-VEHICLE signal to the second companion pavement marker.
 5. A pavement marker as recited in claim 4, wherein the electronic circuit is adapted to respond to the receiver receiving an INCOMING SLOWED-VEHICLE signal from the first companion pavement marker by activating the light-emitting circuit, disregarding the sensor, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of the new counter valve to the second companion pavement marker.
 6. A pavement marker as recited in claim 5, wherein the electronic circuit is adapted to not transmit the RELAYED OUTGOING SLOWED-VEHICLE signal if the counter valve reaches a predetermined maximum valve.
 7. A pavement marker as recited in claim 5, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for less than the first predetermined period of time after transmitting the INITIAL OUTGOING SLOWED-VEHICLE signal by deactivating the light-emitting circuit and transmitting an ALL-CLEAR signal to the second companion pavement marker.
 8. A pavement marker as recited in claim 1, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for more than a second predetermined period of time by activating the light-emitting circuit and transmitting an INITIAL OUTGOING STOPPED-VEHICLE signal to the second companion pavement marker.
 9. A pavement marker as recited in claim 8, wherein the electronic circuit is adapted to respond to the receiver receiving an INCOMING STOPPED-VEHICLE signal from the first companion pavement marker by activating the light-emitting circuit, disregarding the sensor, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING STOPPED-VEHICLE signal indicative of the new counter valve to the second companion pavement marker.
 10. A pavement marker as recited in claim 9, wherein the electronic circuit is adapted to not transmit the RELAYED OUTGOING STOPPED-VEHICLE signal if the counter valve reaches a predetermined maximum valve.
 11. A pavement marker as recited in claim 9, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for less than the first predetermined period after transmitting the INITIAL OUTGOING STOPPED-VEHICLE signal by deactivating the light-emitting circuit and transmitting an ALL-CLEAR signal to the second companion pavement marker.
 12. A method for providing an advance warning of traffic conditions to oncoming traffic, comprising: providing a plurality of battery-powered, solar-charged pavement markers that are adapted to be mounted on a highway pavement, such that each pavement marker is adapted to sense nearby traffic and emit light as a warning of traffic conditions and such that each of the pavement markers includes an electronic circuit that is adapted to operate under program control as means for receiving and responding to a signal from a first companion pavement marker that is more distant from the oncoming traffic, and transmitting a signal to a second companion pavement marker that is less distant from the oncoming traffic, in order to thereby relay a SLOWED-TRAFFIC warning and a STOPPED-TRAFFIC warning of traffic conditions via the pavement markers toward the oncoming traffic; mounting the plurality of pavement markers on the highway pavement in spaced-apart locations along the highway intermediate first and second highway lanes so that the light emitted is visible to oncoming traffic; and relaying information related to nearby traffic from the first companion marker to the second companion pavement marker as an advance warning to the oncoming traffic of traffic conditions.
 13. A traffic warning system, comprising: a plurality of similar pavement markers mounted at spaced apart positions on a highway pavement, including at least a first pavement marker, a second pavement marker, and a third pavement marker; each of the first, second, and third pavement markers including a respective one of first, second, and third support structures such that the support structures are adapted to be mounted on a highway pavement in spaced apart positions visible to oncoming traffic; the second pavement marker including means on the second support structure for producing light directed toward the oncoming traffic, including at least one light-emitting circuit; the second pavement marker including means for sensing nearby traffic in order to provide information related to nearby vehicle speed, including a sensor; the second pavement marker including means for receiving an incoming signal from the first pavement marker, including a receiver; the second pavement markers including means for transmitting an outgoing signal to the third pavement marker, including a transmitter; and the second pavement marker including an electronic circuit adapted to operates under program control as means for controlling operation of the light-emitting circuit and the transmitter according to information obtained from the sensor and the receiver in order to activate the light-emitting circuit and relay a warning of traffic conditions via the transmitter to the third pavement marker and thereby toward the oncoming traffic; wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for more than a first predetermined period of time by activating the light-emitting circuit and transmitting an INITIAL OUTGOING SLOWED-VEHICLE signal to the third pavement marker; wherein the electronic circuit is adapted to respond to the receiver receiving an INCOMING SLOWED-VEHICLE signal from the first pavement marker by activating the light-emitting circuit, disregarding the sensor, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of the new counter valve to the third pavement marker; and wherein the electronic circuit is adapted to not transmit the RELAYED OUTGOING SLOWED-VEHICLE signal if the counter valve reaches a predetermined maximum valve.
 14. A pavement marker as recited in claim 13, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for less than the first predetermined period of time after transmitting the INITIAL OUTGOING SLOWED-VEHICLE signal by deactivating the light-emitting circuit and transmitting an ALL-CLEAR signal to the third companion pavement marker.
 15. A pavement marker as recited in claim 13, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for more than a second predetermined period of time by activating the light-emitting circuit and transmitting an INITIAL OUTGOING STOPPED-VEHICLE signal to the third pavement marker.
 16. A pavement marker as recited in claim 13, wherein the electronic circuit is adapted to respond to the receiver receiving an INCOMING STOPPED-VEHICLE signal from the first pavement marker by activating the light-emitting circuit, disregarding the sensor, incrementing a counter valve to produce a new counter valve, and transmitting a RELAYED OUTGOING STOPPED-VEHICLE signal indicative of the new counter valve to the third pavement marker.
 17. A pavement marker as recited in claim 16, wherein the electronic circuit is adapted to not transmit the RELAYED OUTGOING STOPPED-VEHICLE signal if the counter valve reaches a predetermined maximum valve.
 18. A pavement marker as recited in claim 13, wherein the electronic circuit is adapted to respond to the sensor detecting an occurrence of the presence of a nearby vehicle for less than the first predetermined period after transmitting the INITIAL OUTGOING STOPPED-VEHICLE signal by deactivating the light-emitting circuit and transmitting an ALL-CLEAR signal to the third pavement marker. 